docs: def is_timeseries(nc, variable):
      '''
      Returns true if the variable is a time series feature type.
  
      :param netCDF4.Dataset nc: An open netCDF dataset
      :param str variable: name of the variable to check
      '''
  
      # x, y, z, t(t)
      # X(t)
      dims = nc.variables[variable].dimensions
      cmatrix = coordinate_dimension_matrix(nc)
      time_variables = get_time_variables(nc)
  
      if len(dims) != 1:
          return False
      dim = dims[0]
      if dim not in time_variables:
          return False
      # No other coordinates can vary with time
      if 'x' in cmatrix:
          if len(cmatrix['x']) != 0:
              return False
      if 'y' in cmatrix:
          if len(cmatrix['y']) != 0:
              return False
      if 'z' in cmatrix:
          if len(cmatrix['z']) != 0:
              return False
  
      return True